title: SPECT/CT in patients with lower back pain after lumbar fusion surgery.
abstract: OBJECTIVE
  The aim of the study was to investigate the incremental diagnostic value of skeletal hybrid imaging with single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) over conventional nuclear medical imaging in patients with lower back pain after lumbar fusion surgery (LFS).
  
  
  METHODS
  This retrospective study comprised 37 patients suffering from lower back pain after LFS in whom three-phase planar bone scintigraphies of the lumbar spine including SPECT/CT of that region had been performed. The findings visible on these imaging data sets were classified into the following five diagnostic categories: (a) metal loosening; (b) insufficient stabilizing function of the metal implants indicated by metabolically active facet joint arthritis and/or intervertebral osteochondrosis in the instrumented region; (c) adjacent instability defined as metabolically active degenerative disease in the segments adjacent to the instrumented region; (d) indeterminate; and (e) normal.
  
  
  RESULTS
  In the case of eight patients no lesions were visible on their planar scintigraphy and SPECT (planar/SPECT) or SPECT/CT images. In the remaining 29 patients, planar/SPECT disclosed 62 pathological foci of uptake within the graft region and SPECT/CT revealed 55. The rate of reclassification by SPECT/CT compared with planar/SPECT was 5/12 for lesions categorized as metal loosening by planar/SPECT, 16/29 for foci with a planar/SPECT diagnosis of insufficient stabilizing function, 7/20 when the planar/SPECT diagnosis had been adjacent instability, and 1/1 for the lesions indeterminate on planar/SPECT. Two lesions had been detected on SPECT/CT only. The overall rate of reclassification was 45.2% (28/62) (95% confidence interval, 33.4-57.5%).
  
  
  CONCLUSIONS
  Because of its significantly higher accuracy compared with planar/SPECT, SPECT/CT should be the conventional nuclear medical procedure of choice for patients with lower back pain after LFS.
authors.affiliation: Clinic of Nuclear Medicine, Friedrich-Alexander-University Erlangen-Nürnberg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Sumer
authors.forename: Daniela
authors.initials: D
authors.lastname: Schmidt
authors.forename: Philipp
authors.initials: P
authors.lastname: Ritt
authors.forename: Michael
authors.initials: M
authors.lastname: Lell
authors.forename: Raimund
authors.initials: R
authors.lastname: Forst
authors.forename: Torsten
authors.initials: T
authors.lastname: Kuwert
authors.forename: Richard
authors.initials: R
authors.lastname: Richter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D064847:Multimodal Imaging; D011183:Postoperative Complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects*; D015899:Tomography, Emission-Computed, Single-Photon; D036542:Tomography, Spiral Computed; D055815:Young Adult